A device having a tray defining at least one reservoir designed to contain a liquid, a platform, designed to be placed on the tray and to support a growing substrate, the platform including a flat main portion provided with wells having, at the bottom, an orifice communicating with the liquid contained in the tray, and means for carrying liquid in the reservoir, where a plurality of reinforcing walls protrude perpendicularly upwards from the main portion of the platform, where these walls have sufficient height so that, when the platform is placed on the tray, their top edge forms the highest portion of the device, and where the reinforcing walls are distributed on the surface of the platform so as to allow a distribution of the loads applied to this device.
